Semi-adaptable articulators and facebows
1-Introduction:
To make the prosthesis, it is necessary to transfer the intermaxillary relationships from the office to the laboratory using a mechanical device: the articulator.
2)-Definitions:
*Articulator:
It is a diagnostic and treatment instrument intended to transfer and analyze in the laboratory the static and dynamic relationships between the mandible and the maxilla.
*The Face Bow:
It is a removable device used to position the upper model on the upper branch of the articulator in the same position that the natural arch occupies relative to the Frankfurt plane, it can be used to determine the center of rotation of the condyles.
3)-Classification:
-The articulators:
*Occluders: Are simple hinged devices, they only allow the static relationships existing between two arches to be fixed.
*Non-adaptable articulators: Their condylar housings are machined in such a way that they respond to static means; the practitioner cannot intervene on their adjustment or modify their shapes. Exp. The Quick from Fag.
*Semi-adaptable articulators:
-they allow the reproduction of the direction and the end of the condylar movements, but not the intermediate path => rectilinear movement;
– the intercondylar distance is not fully adjustable (eg Whip-Mix).
*Fully programmable articulators:
-They reproduce the details of limited movements including immediate and progressive lateral displacements, as well as the curvature and direction of the condylar path;
-The intercondylar distance is fully adjustable. Exp. Denar-Stuart pantographs.
-The facial bows:
-Transfer facial bow: It allows to fix the orientation relationships of the upper jaw in relation to the base of the skull, e.g. Hanau facial bow.
-Determination facial arc: It allows the identification of rotation centers. Example: Stuart arc.
-Kinematic arcs: They allow the recording of condylar trajectories. Example: axiographs .
4-Fundamental notions:
The analysis of static and dynamic inter-arch relationships as well as the study of condylar trajectories cannot be conducted directly in the mouth, hence the need to know the mandibular kinematics and that of the articulators, and for a better understanding certain notions will be clarified.
4-1-Hinge axis: This is a virtual axis passing through the center of rotation of each condyle in the small opening and closing movements of the mandible.
*Location of the hinge axis:
This axis is transferred to the articulator using a device called a Facial Arc.
°Localization by palpation: In 1899 Snow attempted to determine the hinge axis by gentle palpation of the pretragal region during mandibular movements.
=> A margin of error is 1 to 2mm at a correct DV.
°Arbitrary location:
– Conventional cutaneous localization: For SNOW and HANAU, the center of rotation of the condyles is located 10 to 13 mm in front of the tragus on a line going from the tragus to the external angle of the eye. – Auricular localization: This type of localization involves auricular olives placed in the external auditory canals. (The articulators: “Denar, Sam, Whip-mix”.
4-2)-The determinants of occlusion:
According to Nally on the determinants of occlusion:
“Since the mandibular movements are guided by posterior (condylar) and anterior (dental) guidance, the articulators have condylar elements and an incisal plate which allow the reproduction of these movements with greater or lesser fidelity.”
*Posterior determinants:
-The condylar slope: It represents the path traveled by the mandibular condyle along the temporal condyle during a propulsion movement. This is guided by a sliding of the incisal edges of the lower teeth on the palatal surfaces of the upper incisors and which results in an incisal end to end while a space is formed at the molar level (Christensen phenomenon).
This path forms an average angle of 40° with the Frankfurt plane, and an angle of between 20 and 35° with the Camper plane, this angle is called: Condylian Slope.
– Bennett angle: in the mandibular diduction movements, the right and left condyles move asymmetrically.
The working condyle located on the side where the movement takes place (working side) performs a movement always directed outwards, upwards or downwards, forwards or backwards; this movement is called the “BENNETT movement”.
It is a low amplitude movement (1 to 2 mm).
The condyle opposite the working condyle (non-working condyle) always moves inwards, forwards and downwards, its trajectory seen from the front forms with a plane parallel to the sagittal plane passing through the center of the condyle, an angle which varies on average between 12° and 18°: this is the “BENNETT angle”.
*Anterior determinants: This is the anterior dental guidance which is expressed in the sagittal plane by the incisal slope and in diduction by the canine guidance and the incisal guidance:
-The incisal slope or incisal trajectory: It results from the sliding path of the free edge of the lower incisors on the palatal slopes of the upper incisors. It forms an angle with the occlusal plane.
The angle formed by the line joining the two incisal edges with this plane is the incisal angle.
-Dental guidance in diduction: in lateral direction, certain teeth come into contact and guide the mandible, this guidance can be carried out by the canine (canine guidance or canine protection) by the incisors (incisal guidance), or by a group of teeth including the canine (group guidance or group function).
5)-Description:
5.1. The semi-adaptable articulator:
It is a device that allows the more or less precise mechanical reproduction of mandibular kinematics.
-composite: ° upper branch => represents the middle part of the face;
°lower branch => represents the lower level of the face (mandible);
-designed according to a reference plane: axio-orbital plane, which passes through the two emergences of the hinge axis and through one of the two suborbital points;
-an incisive rod which determines the height of the DV.
The Arcon semi-adaptable articulator : the condylar balls are supported by the lower branch (mechanical equivalent of the mandible);
The Anti-arcon semi-adaptable articulator : the condylar loops are supported by the upper branch.
-condylar boxes, configuring the temporal fossae of the skull.
Roles :
-Analyze the situation of the occlusal plane, the relationships between the teeth in centric relation during lateral excursions and in propulsion .
– Carry out corrections of occlusal surfaces (arrangement of the occlusal plane and equilibration in centric relation) on study models and objectify the desired dental relationships.
-methodological development in the laboratory of the assembly of prosthetic teeth to establish dental relationships in accordance with the chosen occlusal concept.
the imperatives that an articulator must obey
-Ensure the transfer of the position of the two arches in correct relation with reference points and planes taken on the facial mass and reproduced on the upper branch of the articulator. -Allow the transfer of the hinge axis located arbitrarily or kinematically.
-Have an adjustable intercondylar distance.
-Be of the “aron” type, that is to say have the condylar spheres fixed on the lower branch of the articulator, so that the condylar trajectories maintain constant relationships with the occlusal plane, when the vertical dimension varies.
-Ensure the transfer and reproduction of the main condylar trajectories in the three planes of space.
-Ensure a simple report of incisor trajectories.
-Be a scientific element of diagnosis and treatment.
-Maintain the stability and constancy of the reference terminal axial position regardless of variations in the condylar slope.
-Allow easy manipulations in the laboratory both at the time of articulating and during the main transfers, with easy visual or manual access to the lingual part of the assembly.
-be easy to use
– be compact and lightweight;
-easy to clean
Limits of use:
-the articulator concept cannot perfectly mimic the patient’s anatomy and physiology;
-the condylar boxes do not have the exact cavity of the temporal fossa;
-the condylar loops do not have the ovoid shape of the mandibular condyles.
-the articulator allows us to get as close as possible to the patient’s dynamic diagram.
-For physiologists, “the articulator is a mechanism that has its own limits. We must not give it a human face.”
Description of the Hanau 96 1-I2 XPR articulator :
-lower branch: It is fixed, consisting of a horizontal base comprising:
–At the front: An adjustable incisal guide plate, it can be blocked according to a reference point divided into degrees, this plate has two independent flaps which can be adjusted according to the diduction movements, according to reference points divided into degrees.
–In the middle of the base: A removable metal plate is fixed, Intended to fix the lower plaster model, also called a mounting plate.
–At the rear of the base: There are two vertical columns or brackets which can be moved around their axes (condylar pillars). They can be locked in different specific positions corresponding to the BENNETT angle (a graduation in degrees will specify the value of this angle).
–The upper part of these columns is made up of a metal ring (condylar ring) in which slides a diagonally split disc with a groove allowing a kneecap to slide,
–The rotation in the vertical plane of the condylar disc in its ring allows the transfer of the condylar angle to the articulator.
–The metal ball joint representing the condyle (condylar sphere) belongs to the upper branch of the articulator (anti-arcon specificity).
–At the front part of the gutter, there is a screw which blocks the condylar patella behind its normal position (protrusion screw).
-Upper branch : It is mobile and consists of a horizontal bar parallel to the lower branch, it includes:
–At the front: An adjustable incisal guide rod which rests with its incisal pin on the incisal plate, a rod locking system.
–In the middle: A mounting plate of the upper model, with an
indicator of the orbital plane (or strong Franc plane) in front.
–At the back: A rod perpendicular to the anteroposterior horizontal bar and supporting the two condylar spheres which slide in the slots of the discs of the lower branch, this rod after having crossed the condylar spheres is extended by right and left axes which will be used to position the facial bow.
–The condylar patellas are mobile laterally on their axis and this mobility
will allow the Bennett movements to be materialized and the value of the Bennett angle to be determined.
5.2. The Face Bow is composed of:
– an extra-oral arch with an anterior arm and two sagittal arms;
-a model holder fork (intra-oral);
– an orbital index or nasal stop;
– a condylar stop or auricular olives;
– adjustment and tightening screws;
-a condylar stylet
6)-Use of the semi-adaptable articulator
Articulator presetting: eg. Dentatus 40° TC, 20° Bennett angle, Hanau: 30°, 15°.
The upper model assembly, 02 solutions: -face bow or the assembly table.
6-1)-Assembly of upper model:
Fitting the facebow and assembling the upper model:
The facebow will allow the transfer of the position of the upper model onto the articulator:
-The facial bow is placed arbitrarily: The condylar rulers are placed in contact with the condylar landmarks already determined.
-Positioning and securing the fork: the occlusion rim of the model > is fixed on the occlusal fork of the facebow.
-It is then introduced into the mouth. Well centered, the handle of the fork must be placed in the median sagittal plane.
– the fork is disengaged.
-The maxillary model must be replaced on the occlusion model.
-Setting up the face bow:
-The fork handle is slid into its locking device.
-The ends of the condylar rods are applied against the condylar landmarks already determined on the patient.
-The orbital index is introduced into its locking device and placed in contact with the suborbital point and locked in this position.
-The anterior part of the facebow frame should be horizontal and parallel to the bipupillary line.
-A final check is required before the final locking of all the screws and before the removal of the assembly, which must be carried out without any movement of the different elements of the arch.
– Facebow transfer: Before transfer, arbitrary programming of the articulator:
the condylar slopes will be fixed at 30°, the Bennett angles at 15°.
-The incisal plate inclination at 0°.
-The mounting plates will be adapted to the upper and lower branches.
-Vaseline the surfaces exposed to the materials used for assembly.
-Preparation of the split-caste: Before proceeding with the assembly of the upper and lower models, i.e. the placement in the articulator, it is necessary to make the split-caste which are separable bases or secondary bases and for this:
-V-shaped notches are cut into the primary base of the models.
-Then isolate the plaster and make a boxing to be able to cast the separable bases using the hard plaster. This separable base model assembly will be mounted on a semi-adaptable articulator.
Role of the bases:
–Check the recording of the centric relation.
-Adjustment of the inclination of the condylar slopes.
-Immediate balancing on semi-adaptable articulator.
_-Assembly of the upper model:
-Vaseline the upper mounting plate of the articulator.
-This branch is raised and folded back.
-The working model with the occlusion model is placed on the fork, this being well wedged on its support.
-Then a quantity of quick-setting plaster is applied and the upper branch of the articulator is lowered until intimate contact is obtained between the incisal guide and the anterior incisal guide plane.
-The pointer of the suborbital index finger should touch the suborbital plane. The facebow is removed.
6.2/-Assembly of the lower model: After having completed the assembly of the maxillary model, we move on to recording the intermaxillary relationship and assembly of the lower model.
-The assembly of the lower model will be done in centric relation (totally edentulous).
-occlusion rims adjusted to a correct vertical dimension and inserted in the mouth.
-The mandible is guided in centric relation.
-After saving, the > and < models are linked.
-A quantity of plaster is placed on the lower mounting plate.
-The upper branch of the articulator is lowered until there is intimate contact between the incisal pin and the incisal guide plane.
-Using a spatula , remove excess plaster.
-The two models are maintained until the plaster has completely set.
6-3)-Programming the articulator:
=> Two methods:
-wax bites (intraoral);
-pantograph: Quick Axis (extra buccal) numerical values are read on the micrometer drum.
*Intraoral method:
-Lauritzen method: myoco wax bites coating a tin foil (0.1mm thick):
-a pair of bites on PM and M in incisal end to end
-two pairs of laterally bitten end to end canine indented wax.
-Morin and Valentin method: with a greater thickness of wax.
-Universal Jig method: => plaster bites.
*Condylar slope:
– the incisive rod is raised and fixed;
-the condylar columns are rotated outwards, to fix them at 0° (Bennett angle = 0);
-the condylar spheres are unlocked;
– the upper branch of the articulator to which the secondary base is fixed is reversed (split-cast);
-Place the two occlusion models in the mouth and have the patient bite in protrusion which must be symmetrical without deviation;
-then place the two models on their respective models fixed in propulsion,
– the upper branch of the articulator equipped with the secondary base of the upper model is tilted forward until the split-cast closes (the condylar spheres being unlocked);
– the adjustment of the inclinations of the condylar slopes is carried out;
-once the adjustment is complete the two screws will be locked.
*Bennett Angle: This setting will be determined:
– either by recording waxes of the right and left laterotrusions;
– either arbitrarily using the Hanau formula L = H/8 + 12, = L: Bennett angle, H = inclination in degrees of the condylar slope.
Note: Laterality must be pure, symmetrical and greater than 04mm.
*Anterior guidance setting:
After mounting the anterior teeth and checking the aesthetics and phonation. The incisal guide rod is placed against the incisal guide plane (unlocks). End to end the plane must be in contact with the rod.
7)-Conclusion: An articulator is a diagnostic and treatment instrument intended to transfer and analyze in the laboratory, the static and dynamic relationships between the mandible and the maxilla. (J. Lejoyeux).
The articulator is an essential link in the analysis of some of the clinical cases, in their orthopedic, preprosthetic, and prosthetic treatment. Semi-adaptable articulators and facial bows
1-Introduction:
To make the prosthesis, it is necessary to transfer the intermaxillary relationships from the office to the laboratory using a mechanical device: the articulator.
2)-Definitions:
*Articulator:
It is a diagnostic and treatment instrument intended to transfer and analyze in the laboratory the static and dynamic relationships between the mandible and the maxilla.
*The Face Bow:
It is a removable device used to position the upper model on the upper branch of the articulator in the same position that the natural arch occupies relative to the Frankfurt plane, it can be used to determine the center of rotation of the condyles.
3)-Classification:
-The articulators:
*Occluders: Are simple hinged devices, they only allow the static relationships existing between two arches to be fixed.
*Non-adaptable articulators: Their condylar housings are machined in such a way that they respond to static means; the practitioner cannot intervene on their adjustment or modify their shapes. Exp. The Quick from Fag.
*Semi-adaptable articulators:
-they allow the reproduction of the direction and the end of the condylar movements, but not the intermediate path => rectilinear movement;
– the intercondylar distance is not fully adjustable (eg Whip-Mix).
*Fully programmable articulators:
-They reproduce the details of limited movements including immediate and progressive lateral displacements, as well as the curvature and direction of the condylar path;
-The intercondylar distance is fully adjustable. Exp. Denar-Stuart pantographs.
-The facial bows:
-Transfer facial bow: It allows to fix the orientation relationships of the upper jaw in relation to the base of the skull, e.g. Hanau facial bow.
-Determination facial arc: It allows the identification of rotation centers. Example: Stuart arc.
-Kinematic arcs: They allow the recording of condylar trajectories. Example: axiographs .
4-Fundamental notions:
The analysis of static and dynamic inter-arch relationships as well as the study of condylar trajectories cannot be conducted directly in the mouth, hence the need to know the mandibular kinematics and that of the articulators, and for a better understanding certain notions will be clarified.
4-1-Hinge axis: This is a virtual axis passing through the center of rotation of each condyle in the small opening and closing movements of the mandible.
*Location of the hinge axis:
This axis is transferred to the articulator using a device called a Facial Arc.
°Localization by palpation: In 1899 Snow attempted to determine the hinge axis by gentle palpation of the pretragal region during mandibular movements.
=> A margin of error is 1 to 2mm at a correct DV.
°Arbitrary location:
– Conventional cutaneous localization: For SNOW and HANAU, the center of rotation of the condyles is located 10 to 13 mm in front of the tragus on a line going from the tragus to the external angle of the eye. – Auricular localization: This type of localization involves auricular olives placed in the external auditory canals. (The articulators: “Denar, Sam, Whip-mix”.
4-2)-The determinants of occlusion:
According to Nally on the determinants of occlusion:
“Since the mandibular movements are guided by posterior (condylar) and anterior (dental) guidance, the articulators have condylar elements and an incisal plate which allow the reproduction of these movements with greater or lesser fidelity.”
*Posterior determinants:
-The condylar slope: It represents the path traveled by the mandibular condyle along the temporal condyle during a propulsion movement. This is guided by a sliding of the incisal edges of the lower teeth on the palatal surfaces of the upper incisors and which results in an incisal end to end while a space is formed at the molar level (Christensen phenomenon).
This path forms an average angle of 40° with the Frankfurt plane, and an angle of between 20 and 35° with the Camper plane, this angle is called: Condylian Slope.
– Bennett angle: in the mandibular diduction movements, the right and left condyles move asymmetrically.
The working condyle located on the side where the movement takes place (working side) performs a movement always directed outwards, upwards or downwards, forwards or backwards; this movement is called the “BENNETT movement”.
It is a low amplitude movement (1 to 2 mm).
The condyle opposite the working condyle (non-working condyle) always moves inwards, forwards and downwards, its trajectory seen from the front forms with a plane parallel to the sagittal plane passing through the center of the condyle, an angle which varies on average between 12° and 18°: this is the “BENNETT angle”.
*Anterior determinants: This is the anterior dental guidance which is expressed in the sagittal plane by the incisal slope and in diduction by the canine guidance and the incisal guidance:
-The incisal slope or incisal trajectory: It results from the sliding path of the free edge of the lower incisors on the palatal slopes of the upper incisors. It forms an angle with the occlusal plane.
The angle formed by the line joining the two incisal edges with this plane is the incisal angle.
-Dental guidance in diduction: in lateral direction, certain teeth come into contact and guide the mandible, this guidance can be carried out by the canine (canine guidance or canine protection) by the incisors (incisal guidance), or by a group of teeth including the canine (group guidance or group function).
5)-Description:
5.1. The semi-adaptable articulator:
It is a device that allows the more or less precise mechanical reproduction of mandibular kinematics.
-composite: ° upper branch => represents the middle part of the face;
°lower branch => represents the lower level of the face (mandible);
-designed according to a reference plane: axio-orbital plane, which passes through the two emergences of the hinge axis and through one of the two suborbital points;
-an incisive rod which determines the height of the DV.
The Arcon semi-adaptable articulator : the condylar balls are supported by the lower branch (mechanical equivalent of the mandible);
The Anti-arcon semi-adaptable articulator : the condylar loops are supported by the upper branch.
-condylar boxes, configuring the temporal fossae of the skull.
Roles :
-Analyze the situation of the occlusal plane, the relationships between the teeth in centric relation during lateral excursions and in propulsion .
– Carry out corrections of occlusal surfaces (arrangement of the occlusal plane and equilibration in centric relation) on study models and objectify the desired dental relationships.
-methodological development in the laboratory of the assembly of prosthetic teeth to establish dental relationships in accordance with the chosen occlusal concept.
the imperatives that an articulator must obey
-Ensure the transfer of the position of the two arches in correct relation with reference points and planes taken on the facial mass and reproduced on the upper branch of the articulator. -Allow the transfer of the hinge axis located arbitrarily or kinematically.
-Have an adjustable intercondylar distance.
-Be of the “aron” type, that is to say have the condylar spheres fixed on the lower branch of the articulator, so that the condylar trajectories maintain constant relationships with the occlusal plane, when the vertical dimension varies.
-Ensure the transfer and reproduction of the main condylar trajectories in the three planes of space.
-Ensure a simple report of incisor trajectories.
-Be a scientific element of diagnosis and treatment.
-Maintain the stability and constancy of the reference terminal axial position regardless of variations in the condylar slope.
-Allow easy manipulations in the laboratory both at the time of articulating and during the main transfers, with easy visual or manual access to the lingual part of the assembly.
-be easy to use
– be compact and lightweight;
-easy to clean
Limits of use:
-the articulator concept cannot perfectly mimic the patient’s anatomy and physiology;
-the condylar boxes do not have the exact cavity of the temporal fossa;
-the condylar loops do not have the ovoid shape of the mandibular condyles.
-the articulator allows us to get as close as possible to the patient’s dynamic diagram.
-For physiologists, “the articulator is a mechanism that has its own limits. We must not give it a human face.”
Description of the Hanau 96 1-I2 XPR articulator :
-lower branch: It is fixed, consisting of a horizontal base comprising:
–At the front: An adjustable incisal guide plate, it can be blocked according to a reference point divided into degrees, this plate has two independent flaps which can be adjusted according to the diduction movements, according to reference points divided into degrees.
–In the middle of the base: A removable metal plate is fixed, Intended to fix the lower plaster model, also called a mounting plate.
–At the rear of the base: There are two vertical columns or brackets which can be moved around their axes (condylar pillars). They can be locked in different specific positions corresponding to the BENNETT angle (a graduation in degrees will specify the value of this angle).
–The upper part of these columns is made up of a metal ring (condylar ring) in which slides a diagonally split disc with a groove allowing a kneecap to slide,
–The rotation in the vertical plane of the condylar disc in its ring allows the transfer of the condylar angle to the articulator.
–The metal ball joint representing the condyle (condylar sphere) belongs to the upper branch of the articulator (anti-arcon specificity).
–At the front part of the gutter, there is a screw which blocks the condylar patella behind its normal position (protrusion screw).
-Upper branch : It is mobile and consists of a horizontal bar parallel to the lower branch, it includes:
–At the front: An adjustable incisal guide rod which rests with its incisal pin on the incisal plate, a rod locking system.
–In the middle: A mounting plate of the upper model, with an
indicator of the orbital plane (or strong Franc plane) in front.
–At the back: A rod perpendicular to the anteroposterior horizontal bar and supporting the two condylar spheres which slide in the slots of the discs of the lower branch, this rod after having crossed the condylar spheres is extended by right and left axes which will be used to position the facial bow.
–The condylar patellas are mobile laterally on their axis and this mobility
will allow the Bennett movements to be materialized and the value of the Bennett angle to be determined.
5.2. The Face Bow is composed of:
– an extra-oral arch with an anterior arm and two sagittal arms;
-a model holder fork (intra-oral);
– an orbital index or nasal stop;
– a condylar stop or auricular olives;
– adjustment and tightening screws;
-a condylar stylet
6)-Use of the semi-adaptable articulator
Articulator presetting: eg. Dentatus 40° TC, 20° Bennett angle, Hanau: 30°, 15°.
The upper model assembly, 02 solutions: -face bow or the assembly table.
6-1)-Assembly of upper model:
Fitting the facebow and assembling the upper model:
The facebow will allow the transfer of the position of the upper model onto the articulator:
-The facial bow is placed arbitrarily: The condylar rulers are placed in contact with the condylar landmarks already determined.
-Positioning and securing the fork: the occlusion rim of the model > is fixed on the occlusal fork of the facebow.
-It is then introduced into the mouth. Well centered, the handle of the fork must be placed in the median sagittal plane.
– the fork is disengaged.
-The maxillary model must be replaced on the occlusion model.
-Setting up the face bow:
-The fork handle is slid into its locking device.
-The ends of the condylar rods are applied against the condylar landmarks already determined on the patient.
-The orbital index is introduced into its locking device and placed in contact with the suborbital point and locked in this position.
-The anterior part of the facebow frame should be horizontal and parallel to the bipupillary line.
-A final check is required before the final locking of all the screws and before the removal of the assembly, which must be carried out without any movement of the different elements of the arch.
– Facebow transfer: Before transfer, arbitrary programming of the articulator:
the condylar slopes will be fixed at 30°, the Bennett angles at 15°.
-The incisal plate inclination at 0°.
-The mounting plates will be adapted to the upper and lower branches.
-Vaseline the surfaces exposed to the materials used for assembly.
-Preparation of the split-caste: Before proceeding with the assembly of the upper and lower models, i.e. the placement in the articulator, it is necessary to make the split-caste which are separable bases or secondary bases and for this:
-V-shaped notches are cut into the primary base of the models.
-Then isolate the plaster and make a boxing to be able to cast the separable bases using the hard plaster. This separable base model assembly will be mounted on a semi-adaptable articulator.
Role of the bases:
–Check the recording of the centric relation.
-Adjustment of the inclination of the condylar slopes.
-Immediate balancing on semi-adaptable articulator.
_-Assembly of the upper model:
-Vaseline the upper mounting plate of the articulator.
-This branch is raised and folded back.
-The working model with the occlusion model is placed on the fork, this being well wedged on its support.
-Then a quantity of quick-setting plaster is applied and the upper branch of the articulator is lowered until intimate contact is obtained between the incisal guide and the anterior incisal guide plane.
-The pointer of the suborbital index finger should touch the suborbital plane. The facebow is removed.
6.2/-Assembly of the lower model: After having completed the assembly of the maxillary model, we move on to recording the intermaxillary relationship and assembly of the lower model.
-The assembly of the lower model will be done in centric relation (totally edentulous).
-occlusion rims adjusted to a correct vertical dimension and inserted in the mouth.
-The mandible is guided in centric relation.
-After saving, the > and < models are linked.
-A quantity of plaster is placed on the lower mounting plate.
-The upper branch of the articulator is lowered until there is intimate contact between the incisal pin and the incisal guide plane.
-Using a spatula , remove excess plaster.
-The two models are maintained until the plaster has completely set.
6-3)-Programming the articulator:
=> Two methods:
-wax bites (intraoral);
-pantograph: Quick Axis (extra buccal) numerical values are read on the micrometer drum.
*Intraoral method:
-Lauritzen method: myoco wax bites coating a tin foil (0.1mm thick):
-a pair of bites on PM and M in incisal end to end
-two pairs of laterally bitten end to end canine indented wax.
-Morin and Valentin method: with a greater thickness of wax.
-Universal Jig method: => plaster bites.
*Condylar slope:
– the incisive rod is raised and fixed;
-the condylar columns are rotated outwards, to fix them at 0° (Bennett angle = 0);
-the condylar spheres are unlocked;
– the upper branch of the articulator to which the secondary base is fixed is reversed (split-cast);
-Place the two occlusion models in the mouth and have the patient bite in protrusion which must be symmetrical without deviation;
-then place the two models on their respective models fixed in propulsion,
– the upper branch of the articulator equipped with the secondary base of the upper model is tilted forward until the split-cast closes (the condylar spheres being unlocked);
– the adjustment of the inclinations of the condylar slopes is carried out;
-once the adjustment is complete the two screws will be locked.
*Bennett Angle: This setting will be determined:
– either by recording waxes of the right and left laterotrusions;
– either arbitrarily using the Hanau formula L = H/8 + 12, = L: Bennett angle, H = inclination in degrees of the condylar slope.
Note: Laterality must be pure, symmetrical and greater than 04mm.
*Anterior guidance setting:
After mounting the anterior teeth and checking the aesthetics and phonation. The incisal guide rod is placed against the incisal guide plane (unlocks). End to end the plane must be in contact with the rod.
7)-Conclusion: An articulator is a diagnostic and treatment instrument intended to transfer and analyze in the laboratory, the static and dynamic relationships between the mandible and the maxilla. (J. Lejoyeux).
The articulator is an essential link in the analysis of some of the clinical cases, in their orthopedic , preprosthetic, and prosthetic treatment.
Semi-adaptable articulators and facebows
Early cavities in children need to be treated promptly.
Dental veneers cover imperfections such as stains or cracks.
Misaligned teeth can cause difficulty chewing.
Dental implants provide a stable solution to replace missing teeth.
Antiseptic mouthwashes reduce bacteria that cause bad breath.
Decayed baby teeth can affect the health of permanent teeth.
A soft-bristled toothbrush preserves enamel and gums.